<!DOCTYPE html>
<html>
<body>
<style>
#foo {
  overflow: scroll;
  height: 100px;
}
</style>
<div id="foo">
Mozilla Firefox<br>
Mozilla Firefox<br>
Mozilla Firefox<br>
Mozilla Firefox<br>
Mozilla Firefox<br>
Mozilla Firefox<br>
Mozilla Firefox<br>
Mozilla Firefox<br>
Mozilla Firefox<br>
Mozilla Firefox<br>
Mozilla Firefox<br>
Mozilla Firefox<br>
Mozilla Firefox<br>
Mozilla Firefox<br>
Mozilla Firefox<br>
Mozilla Firefox<br>
Mozilla Firefox<br>
Mozilla Firefox<br>
<script>
foo.createShadowRoot().innerHTML = "<content></content>";
</script>
</body>
</html>
